The fluid dynamics of simultaneous irrigation with negative pressure wound therapy.

Saline irrigation has been shown to be both experimentally and clinically efficacious in decreasing bacterial contamination as well as decreasing infection rates. The dynamics of irrigation delivery fall into two primary categories: simultaneous and intermittent irrigation. An important component to irrigation therapy is distribution of irrigation solution to hard-to-reach areas of a wound bed, including undermining and fissure-like structures. Here we test the effectiveness of simultaneous irrigation to fill the irregular structures of a wound bed. In order to visualise the dynamic movement of irrigation solution, three-dimensional wound models were constructed using clear synthetic ballistic gel. Wounds with the aforementioned characteristics were carved into the ballistic gel with varying area, depth and volume. All three wounds were dressed as per manufacturer's instructions. Data demonstrate that simultaneous irrigation is effective in reaching all parts of a wound bed in wound models that have both undermining and tunnelling, and irrigation effectively saturates bridged wounds. Finally, this study shows that there is constant turnover of irrigation solution in the wound that is driven more by administration volume and less by flow rate. These data show that simultaneous irrigation is an effective technique for delivering irrigation solution to both simple and complex wounds.